1. Field of the Invention
The present invention relates to refrigerator display case doors and more particularly to refrigerator display case doors formed from a foamed polymeric material which may allow a door having an all-glass front. This invention also relates to a refrigerator display case door whereby a portion of the rail of the door serves as a spacer between multiple glazing panels.
2. Related Art
Commercial refrigerators and refrigerator display cases are used in markets, food-vending operations, liquor stores and the like for the simultaneous preservation of freshness and attractive display of foods to the customer. Typically, commercial display cases have frames defining an opening for the case which is accessed through large, swinging doors having large areas of multi-layered glazing to permit the customer to see, select and access the refrigerated product easily, while preventing heat transfer into the refrigerated space. Typically, a metal door rail supports and surrounds the multi-layered glazing to support the glazing panels and to protect the edges thereof.
Present commercial glass refrigerator doors typically have door rails which extend peripherally around the glass panels of the doors. Such door rails are used to hold the glass panels in place and extend peripherally around both the inside and outside glass surfaces of the doors. As a result, the door rails can be seen from the outside of the doors, detracting from the appearance of the glass doors.
Door rails have heretofore been formed from extruded or other forms of metal rail elements fastened together at mitered corners of upper and lower horizontal rail members and left and right vertical side members. The hardware for connecting the corners of the rail structure quite often is complicated, using a significant number of interfitting parts to provide a suitable corner connection. Hinge elements support the door for pivotable movement relative to a vertical axis.
The metal rail members, while providing suitable structural support and pleasing aesthetic appearance, readily conduct heat from outside the refrigerated display case as well as serving as a condensation surface for water vapor which may be present in the ambient air. To eliminate condensation and fogging, heater wires are sometimes placed in the door rail to warm the metal rail and to thus inhibit condensation. To change the aesthetic appearance, some rails have been redesigned to place a substantial amount of the metal rail behind the front panel, but there still exists rail material that extends over the front glazing panel.
There is a need for a refrigerated display case door rail which is mounted entirely behind the front glazing panel, which is thermally efficient and minimizes the conduction of heat into the refrigerated display case, which minimizes the condensation and fogging of the door and door rail under conditions of humidity, which provides a strong reliable door rail and which is easy to assemble. There is also a need for a door rail which is light weight and provides a door which has a pleasing aesthetic appearance. There further is a need for a door rail having a rail portion which can also serve as a spacer or separator between adjacent panels in a multiple panel unit.